Steerable guidewires and catheters that have been previously described primarily include one or more mechanical tension wires housed within a lumen of the guidewire/catheter, which can be selectively tensioned from the proximal end to cause the distal tip to deflect/bend. However, due to the complex construction required to form these devices, most have outer diameters of greater than 5 mm, with the smallest presently around 2 mm. These devices are typically used in electrophysiology and other applications where the vessels to be navigated are relatively large, but are not suitable for use in interventional cardiology (IC) and neuroradiology (NR) procedures.
For example, a (non-steerable) guidewire suitable for use in IC and NR procedures is the 1 F (0.014″ or 0.36 mm) guidewire. The corresponding catheter for use with these devices has an inner diameter slightly larger than 1 F, such that it passes over the 1 F guidewire. The sizes of IC and NR guidewires and catheters are considerably smaller than existing steerable devices, as they need to navigate much smaller vessels (as small as 0.5 mm in diameter).
Thus, there is a need for extremely low-profile apparatuses (e.g., micro-guidewires and micro-catheters) that are steerable in vivo. Described herein are apparatuses (e.g., devices and systems) and methods of making and operating them, which address these needs. Any of the apparatuses described herein may be robotically, automatically and/or manually steerable.
The steerable apparatuses, controllers and methods of making and using them described herein may include a number of key features that allow a reduction in the diameter of the apparatuses without compromising functionality.